1. Technical Field
The disclosure relates generally to a retrofit roofing system for use with corrugated metal roofs and low profile ribbed metal roofs, a method for retrofitting these roofs, and a clip for installing a retrofit metal roof over an existing corrugated metal roof or an existing low profile ribbed metal roof. The clip allows the retrofit roof to be installed on an existing roof even when the corrugations or ribs are inconsistently spaced or sized over the width of the roof.
2. Background Information
One of the oldest and most common metal roofing systems used in the United States uses corrugated metal panels supported on purlins. The corrugations are disposed perpendicular to the purlins and the panels overlap at their edges. Due to the age of many of these roof systems, many corrugated roof systems are due for replacement or retrofit. Various roof retrofit systems exist in the roofing art. Some of these systems use elongated spacers that define spaced notches which accommodate existing metal roof seams. The retrofit roof system is supported on top of these spacers. One such system is described in U.S. Pat. No. 7,861,480. These elongated spacers cannot be used effectively with corrugated metal roofing because the defined notches cannot be designed to accurately match up with the raised portions of the corrugations due to inconsistencies in the existing corrugated metal panels. In addition to corrugated metal panels, some existing roofs use low profile ribbed metal roof panels. Retrofitting such roofs also requires a system to install the retrofit roofing panels over the existing panels.